diff --git a/scripts/bundle-manifest.mjs b/scripts/bundle-manifest.mjs
index cf238038..36f2e8b5 100644
--- a/scripts/bundle-manifest.mjs
+++ b/scripts/bundle-manifest.mjs
@@ -13,6 +13,7 @@ const FURNITURE_ART_RETRY_ASSET_TOKEN = '__HOUSEPLAN_FURNITURE_ART_RETRY_ASSET__
 const PDF_RETRY_ASSET_TOKEN = '__HOUSEPLAN_PDF_RETRY_ASSET__';
 const MOON_RETRY_ASSET_TOKEN = '__HOUSEPLAN_MOON_RETRY_ASSET__';
 const LED_RETRY_ASSET_TOKEN = '__HOUSEPLAN_LED_RETRY_ASSET__';
+const LED_FIELD_RETRY_ASSET_TOKEN = '__HOUSEPLAN_LED_FIELD_RETRY_ASSET__';
 
 /**
  * #627: ru/de/fr of the three lazy dictionary namespaces are one chunk per
@@ -119,6 +120,10 @@ export function buildBundleManifest(bundle, fingerprint) {
               // only when a shown space has an active strip.
               : modules.some((id) => id.endsWith('/src/led-strip-runtime.ts'))
                 ? 'led'
+              // #780: the linear field, loaded by the LED runtime only when a
+              // strip is on in a Glow room with a light scene.
+              : modules.some((id) => id.endsWith('/src/led-strip-field.ts'))
+                ? 'led-field'
               // #474: designer furniture artwork — its own lazy chunk, shared by
               // the editor (static import) and the View runtime (dynamic).
               : modules.some((id) => id.endsWith('/src/furniture-plan-art.generated.ts'))
@@ -164,8 +169,13 @@ export function buildBundleManifest(bundle, fingerprint) {
     || path.includes('pdf-export-'));
   const moonRoots = dynamicRoots.filter((path) => byPath.get(path)?._role === 'moon'
     || path.includes('moon-runtime-'));
-  const ledRoots = dynamicRoots.filter((path) => byPath.get(path)?._role === 'led'
-    || path.includes('led-strip-runtime-'));
+  // #780: the field chunk is a dynamic import of the LED chunk, not of the
+  // initial graph, so it is found by its module, like namespace dictionaries.
+  const ledRoots = [
+    ...dynamicRoots.filter((path) => byPath.get(path)?._role === 'led'
+      || path.includes('led-strip-runtime-')),
+    ...files.filter((file) => file._role === 'led-field').map((file) => file.path),
+  ];
   // #627: namespace dictionaries are dynamic imports of LAZY chunks, never of
   // the initial graph, so they are found by their module, not as a root.
   const namespaceLocaleRoots = files.filter((file) => file._role === 'namespace-locale')
@@ -289,6 +299,9 @@ export function editorRuntimeRetryUrlPlugin() {
       const led = chunks.find((chunk) => Object.keys(chunk.modules)
         .some((id) => id.replaceAll('\\', '/').endsWith('/src/led-strip-runtime.ts')));
       if (!led) throw new Error('LED strip runtime chunk was not emitted');
+      const ledField = chunks.find((chunk) => Object.keys(chunk.modules)
+        .some((id) => id.replaceAll('\\', '/').endsWith('/src/led-strip-field.ts')));
+      if (!ledField) throw new Error('LED strip field chunk was not emitted');
       const namespaceLocales = NAMESPACE_LOCALE_CHUNKS.map((entry) => {
         const chunk = chunks.find((candidate) => Object.keys(candidate.modules)
           .some((id) => id.replaceAll('\\', '/').endsWith(entry.module)));
@@ -306,6 +319,7 @@ export function editorRuntimeRetryUrlPlugin() {
       let pdfReplacements = 0;
       let moonReplacements = 0;
       let ledReplacements = 0;
+      let ledFieldReplacements = 0;
       for (const chunk of chunks) {
         if (chunk.code.includes(EDITOR_RETRY_ASSET_TOKEN)) {
           let asset = posix.relative(posix.dirname(chunk.fileName), editor.fileName);
@@ -361,6 +375,12 @@ export function editorRuntimeRetryUrlPlugin() {
           ledReplacements += chunk.code.split(LED_RETRY_ASSET_TOKEN).length - 1;
           chunk.code = chunk.code.replaceAll(LED_RETRY_ASSET_TOKEN, asset);
         }
+        if (chunk.code.includes(LED_FIELD_RETRY_ASSET_TOKEN)) {
+          let asset = posix.relative(posix.dirname(chunk.fileName), ledField.fileName);
+          if (!asset.startsWith('.')) asset = `./${asset}`;
+          ledFieldReplacements += chunk.code.split(LED_FIELD_RETRY_ASSET_TOKEN).length - 1;
+          chunk.code = chunk.code.replaceAll(LED_FIELD_RETRY_ASSET_TOKEN, asset);
+        }
         for (const entry of namespaceLocales) {
           if (!chunk.code.includes(entry.token)) continue;
           let asset = posix.relative(posix.dirname(chunk.fileName), entry.chunk.fileName);
@@ -371,9 +391,10 @@ export function editorRuntimeRetryUrlPlugin() {
       }
       if (editorReplacements !== 1 || onboardingReplacements !== 1 || isometricReplacements !== 1
           || germanReplacements !== 1 || frenchReplacements !== 1 || furnitureArtReplacements !== 1
-          || pdfReplacements !== 1 || moonReplacements !== 1 || ledReplacements !== 1) {
+          || pdfReplacements !== 1 || moonReplacements !== 1 || ledReplacements !== 1
+          || ledFieldReplacements !== 1) {
         throw new Error('lazy retry URL placeholder counts are '
-          + `${editorReplacements}/${onboardingReplacements}/${isometricReplacements}/${germanReplacements}/${frenchReplacements}/${furnitureArtReplacements}/${pdfReplacements}/${moonReplacements}/${ledReplacements}, expected 1/1/1/1/1/1/1/1/1`);
+          + `${editorReplacements}/${onboardingReplacements}/${isometricReplacements}/${germanReplacements}/${frenchReplacements}/${furnitureArtReplacements}/${pdfReplacements}/${moonReplacements}/${ledReplacements}/${ledFieldReplacements}, expected 1/1/1/1/1/1/1/1/1/1`);
       }
       // #627: the same strict rule for every namespace × language token —
       // exactly one second-attempt URL each, never zero and never two.
diff --git a/src/led-strip-field.ts b/src/led-strip-field.ts
new file mode 100644
index 00000000..d2fafc02
--- /dev/null
+++ b/src/led-strip-field.ts
@@ -0,0 +1,243 @@
+/**
+ * The linear light field of LED strips (#780, ТЗ §3, §6): its own lazy chunk.
+ *
+ * Loaded by the LED runtime only when a strip is on in a Glow room and the
+ * card has a light scene — the static card with `light_pools: false` never
+ * loads it (ТЗ §13.1).
+ *
+ * The field is the exact distance field of the strip with the shared falloff:
+ * every piece of the strip paints opaque grey bands of a luminance mask (round
+ * caps and joins, so one piece never doubles itself), pieces meet through
+ * `mix-blend-mode: lighten` — the maximum, i.e. the nearest piece — and each
+ * piece is clipped to the floor its own emitters can see. A hidden part never
+ * lights through another part's visibility, a closed strip has no seam and a
+ * corner no double brightness.
+ */
+import { svg, type TemplateResult } from 'lit';
+import { repeat } from 'lit/directives/repeat.js';
+import {
+  GLOW_FALLOFF, buildGlowClipGeometry, type LightBarrierScene, type LightRoomPolygon,
+} from './glow-scene';
+import {
+  compactPoints, emitterSamples, isClosedStrip, type FaceContext, type Pt,
+} from './led-strip-geometry';
+import type { LedStripView } from './led-strip-runtime';
+
+export const LED_FIELD_FINGERPRINT = '__HOUSEPLAN_SOURCE_FINGERPRINT__';
+
+/** Bands of the luminance field: 16 steps keep a band under 7 % of the range. */
+export const LED_FIELD_BANDS = 16;
+
+const pts = (points: readonly number[][]): Pt[] => points.map((p) => [p[0], p[1]] as Pt);
+
+interface FieldPiece {
+  d: string;
+  clip: string[];
+}
+
+interface FieldGeometry {
+  pieces: FieldPiece[];
+  box: { x: number; y: number; w: number; h: number };
+}
+
+/** Bounded per-space cache: shape × radius × barrier revision (ТЗ §13.2). */
+export class LedFieldCache {
+  private entries = new Map<string, FieldGeometry | null>();
+  private space = '';
+  constructor(private readonly limit = 50) {}
+  get size(): number { return this.entries.size; }
+  /** Recompute counter for the performance witness: geometry, not paint. */
+  recomputes = 0;
+  forSpace(spaceId: string): void {
+    if (spaceId !== this.space) { this.entries.clear(); this.space = spaceId; }
+  }
+  read(key: string, build: () => FieldGeometry | null): FieldGeometry | null {
+    if (this.entries.has(key)) {
+      const value = this.entries.get(key) ?? null;
+      this.entries.delete(key);
+      this.entries.set(key, value);
+      return value;
+    }
+    this.recomputes += 1;
+    const value = build();
+    this.entries.set(key, value);
+    while (this.entries.size > this.limit) {
+      const oldest = this.entries.keys().next().value;
+      if (oldest === undefined) break;
+      this.entries.delete(oldest);
+    }
+    return value;
+  }
+  clear(): void { this.entries.clear(); this.space = ''; }
+}
+
+const pointsKey = (points: readonly number[][]): string =>
+  points.map((p) => `${p[0].toFixed(5)},${p[1].toFixed(5)}`).join(';');
+
+/**
+ * Pieces of a strip for the field: stored segments cut to at most the radius,
+ * each with the union of what its own emitters see (ТЗ §6). A piece whose
+ * emitters are all inside a body emits nothing; a failed clip makes that piece
+ * dark (fail-dark), never an unclipped field.
+ */
+export function buildFieldGeometry(input: {
+  points: readonly number[][];
+  radius: number;
+  scene: LightBarrierScene;
+  polygons: readonly LightRoomPolygon[];
+  faces: FaceContext | null;
+  spaceId: string;
+}): FieldGeometry | null {
+  const path = compactPoints(pts(input.points));
+  if (path.length < 2 || !(input.radius > 0)) return null;
+  const r = input.radius;
+  const pieces: FieldPiece[] = [];
+  let minX = Infinity, minY = Infinity, maxX = -Infinity, maxY = -Infinity;
+  for (let i = 1; i < path.length; i++) {
+    const a = path[i - 1], b = path[i];
+    const len = Math.hypot(b[0] - a[0], b[1] - a[1]);
+    const count = Math.max(1, Math.ceil(len / r));
+    for (let k = 0; k < count; k++) {
+      const p0: Pt = [a[0] + ((b[0] - a[0]) * k) / count, a[1] + ((b[1] - a[1]) * k) / count];
+      const p1: Pt = [a[0] + ((b[0] - a[0]) * (k + 1)) / count, a[1] + ((b[1] - a[1]) * (k + 1)) / count];
+      const samples = emitterSamples([p0, p1], input.faces, r / 4);
+      if (!samples.length) continue;
+      const clip: string[] = [];
+      let failed = false;
+      for (const source of samples) {
+        try {
+          const lit = buildGlowClipGeometry({
+            spaceId: input.spaceId,
+            source: { x: source[0], y: source[1] },
+            radius: r,
+            scene: input.scene,
+            polygons: input.polygons,
+            onBoundsFailure: () => { failed = true; },
+          }).lit;
+          clip.push(...lit);
+        } catch {
+          failed = true;
+        }
+      }
+      if (failed || !clip.length) continue;
+      pieces.push({ d: `M${p0[0]} ${p0[1]} L${p1[0]} ${p1[1]}`, clip });
+      minX = Math.min(minX, p0[0], p1[0]); minY = Math.min(minY, p0[1], p1[1]);
+      maxX = Math.max(maxX, p0[0], p1[0]); maxY = Math.max(maxY, p0[1], p1[1]);
+    }
+  }
+  if (!pieces.length) return null;
+  return { pieces, box: { x: minX - r, y: minY - r, w: maxX - minX + 2 * r, h: maxY - minY + 2 * r } };
+}
+
+/** The shared falloff at a relative distance 0…1 (GLOW_FALLOFF, linear between stops). */
+export function falloffAt(fraction: number): number {
+  const at = Math.max(0, Math.min(1, fraction)) * 100;
+  for (let i = 1; i < GLOW_FALLOFF.length; i++) {
+    const [o0, v0] = GLOW_FALLOFF[i - 1];
+    const [o1, v1] = GLOW_FALLOFF[i];
+    if (at <= o1) return v0 + ((v1 - v0) * (at - o0)) / Math.max(1e-9, o1 - o0);
+  }
+  return 0;
+}
+
+const grey = (value: number): string => {
+  const level = Math.round(Math.max(0, Math.min(1, value)) * 255);
+  return `rgb(${level},${level},${level})`;
+};
+
+/** Stable DOM ids per strip: a re-render must not rebuild masks and clips. */
+const fieldIds = new Map<string, number>();
+const fieldId = (spaceId: string, stripId: string): number => {
+  const key = `${spaceId}|${stripId}`;
+  let id = fieldIds.get(key);
+  if (id == null) {
+    id = fieldIds.size + 1;
+    fieldIds.set(key, id);
+  }
+  return id;
+};
+
+export interface LedFieldInput {
+  views: readonly LedStripView[];
+  scene: LightBarrierScene | null;
+  polygons: readonly LightRoomPolygon[];
+  faces: FaceContext | null;
+  spaceId: string;
+  /** The card that owns the bounded cache (one per card, gone with it). */
+  owner: object;
+}
+
+const fieldCaches = new WeakMap<object, LedFieldCache>();
+export function ledFieldCache(owner: object): LedFieldCache {
+  let cache = fieldCaches.get(owner);
+  if (!cache) {
+    cache = new LedFieldCache();
+    fieldCaches.set(owner, cache);
+  }
+  return cache;
+}
+
+/**
+ * The linear fields of the strips that are on in a Glow room. Fade uses the
+ * shared spot transition (`.glow-spot`, GLOW_FADE_MS) — no animation system of
+ * its own; an off strip keeps its node at opacity 0, so a fade-out completes
+ * and leaves no residual light.
+ */
+export function renderLedField(input: LedFieldInput): TemplateResult {
+  if (!input.scene) return svg`` as unknown as TemplateResult;
+  const cache = ledFieldCache(input.owner);
+  cache.forSpace(input.spaceId);
+  const scene = input.scene;
+  const fields = input.views.flatMap((view) => {
+    if (!view.glow || view.state === 'unavailable') return [];
+    const key = `${view.strip.id}|${pointsKey(view.strip.points)}|${view.radius.toFixed(5)}|${scene.fingerprint}`;
+    const geometry = cache.read(key, () => buildFieldGeometry({
+      points: view.strip.points,
+      radius: view.radius,
+      scene,
+      polygons: input.polygons,
+      faces: input.faces,
+      spaceId: input.spaceId,
+    }));
+    return geometry ? [{ view, geometry }] : [];
+  });
+  if (!fields.length) return svg`` as unknown as TemplateResult;
+  const bands = Array.from({ length: LED_FIELD_BANDS }, (_, k) => {
+    const outer = 1 - k / LED_FIELD_BANDS;
+    const inner = 1 - (k + 1) / LED_FIELD_BANDS;
+    return { half: outer, value: falloffAt((outer + inner) / 2) };
+  });
+  return svg`<g class="led-fields" pointer-events="none" aria-hidden="true">
+    ${repeat(fields, ({ view }) => view.strip.id, ({ view, geometry }) => {
+      const id = `${fieldId(input.spaceId, view.strip.id)}`;
+      const r = view.radius;
+      const on = view.state === 'on' && !!view.appearance;
+      const box = geometry.box;
+      const closed = isClosedStrip(pts(view.strip.points));
+      return svg`<g class="glow-spot led-field ${on ? '' : 'is-leaving'}" data-led-field="${view.strip.id}"
+          data-pieces="${geometry.pieces.length}" data-closed="${closed ? 'true' : 'false'}">
+        <defs>
+          ${geometry.pieces.map((piece, k) => svg`<clipPath id="hp-led-clip-${id}-${k}">
+            ${piece.clip.map((d) => svg`<path d="${d}" clip-rule="evenodd"></path>`)}
+          </clipPath>`)}
+          <mask id="hp-led-mask-${id}" maskUnits="userSpaceOnUse"
+            x="${box.x}" y="${box.y}" width="${box.w}" height="${box.h}"
+            color-interpolation="sRGB" style="mask-type:luminance">
+            <rect x="${box.x}" y="${box.y}" width="${box.w}" height="${box.h}" fill="black"></rect>
+            <g style="isolation:isolate">
+              ${geometry.pieces.map((piece, k) => svg`<g clip-path="url(#hp-led-clip-${id}-${k})"
+                  style="mix-blend-mode:lighten">
+                ${bands.map((band) => svg`<path d="${piece.d}" fill="none" stroke="${grey(band.value)}"
+                  stroke-width="${2 * band.half * r}" stroke-linecap="round" stroke-linejoin="round"></path>`)}
+              </g>`)}
+            </g>
+          </mask>
+        </defs>
+        <rect class="glow-pool led-pool" x="${box.x}" y="${box.y}" width="${box.w}" height="${box.h}"
+          fill="${view.appearance?.c ?? 'transparent'}" fill-opacity="${(view.appearance?.alpha ?? 0).toFixed(4)}"
+          mask="url(#hp-led-mask-${id})"></rect>
+      </g>`;
+    })}
+  </g>` as unknown as TemplateResult;
+}
+
diff --git a/src/led-strip-runtime.ts b/src/led-strip-runtime.ts
index 4de28c22..be513d01 100755
--- a/src/led-strip-runtime.ts
+++ b/src/led-strip-runtime.ts
@@ -17,9 +17,10 @@
 import { nothing, svg, type TemplateResult } from 'lit';
 import { repeat } from 'lit/directives/repeat.js';
 import {
-  GLOW_FALLOFF, buildGlowClipGeometry, resolveGlowCandidates,
+  resolveGlowCandidates,
   type GlowCandidate, type LightBarrierScene, type LightRoomPolygon,
 } from './glow-scene';
+import { ENTRY_BUILD_FINGERPRINT } from './editor-runtime-loader';
 import { NORM_W, iconUnit } from './space-geometry';
 import { roomGlowOf, roomPoly } from './logic';
 import { ISO_ICON_SCALE, ISO_TILE, isoEdgeColor, isoTileShadow } from './iso-tiles';
@@ -28,7 +29,7 @@ import type { VirtualLightSnapshot } from './virtual-light-state';
 import { geometryAllRings, pointInOpaquePlanBody } from './physical-geometry';
 import {
   LED_DEFAULT_RADIUS_CM, LED_EPSILON_CM, LED_THICKNESS_OFF_D, LED_THICKNESS_ON_D,
-  compactPoints, emitterSamples, isClosedStrip, pathD, stripAnchor, stripHitOwner,
+  pathD, stripAnchor, stripHitOwner,
   stripHitRadiusPx, validStripPoints, visibleStripPath,
   type BodyFace, type FaceContext, type Pt,
 } from './led-strip-geometry';
@@ -36,10 +37,35 @@ import type { DevItem, LedStripModel, RoomCfg, SpaceModel } from './types';
 
 export const LED_RUNTIME_FINGERPRINT = '__HOUSEPLAN_SOURCE_FINGERPRINT__';
 
+type LedField = typeof import('./led-strip-field');
+let field: LedField | null = null;
+let fieldLoading: Promise<unknown> | null = null;
+let fieldFailed: string | undefined;
+
+/**
+ * The field chunk (ТЗ §13.1): loaded only when a strip is on in a Glow room
+ * with a light scene. Same contract as the gate: one load, fingerprint
+ * handshake, a hashed-URL retry on the next entry, never in a loop.
+ */
+export function ledField(entry: string, ready: () => void): LedField | null {
+  if (!field && !fieldLoading && fieldFailed !== entry && fieldFailed !== '') {
+    fieldLoading = (fieldFailed === undefined
+      ? import('./led-strip-field')
+      : import(/* @vite-ignore */ new URL(`__HOUSEPLAN_LED_FIELD_RETRY_ASSET__?${Date.now()}`, import.meta.url).href) as Promise<LedField>
+    ).then((module) => {
+      if (module.LED_FIELD_FINGERPRINT === ENTRY_BUILD_FINGERPRINT) field = module;
+      else fieldFailed = '';
+    }, () => { fieldFailed = entry; }).finally(() => { fieldLoading = null; });
+  }
+  if (!field) void fieldLoading?.then(() => field && ready());
+  return field;
+}
+
+const fieldWanted = (views: readonly LedStripView[]): boolean =>
+  views.some((view) => view.glow && view.state === 'on');
+
 const pts = (points: readonly number[][]): Pt[] => points.map((p) => [p[0], p[1]] as Pt);
 
-/** Bands of the luminance field: 16 steps keep a band under 7 % of the range. */
-export const LED_FIELD_BANDS = 16;
 const OUTLINE = '#383838';
 const CORE_IDLE = '#FFFFFF';
 const UNAVAILABLE = '#9e9e9e';
@@ -259,220 +285,6 @@ export function renderLedStripes(input: LedStripeInput): TemplateResult {
   </g>` as unknown as TemplateResult;
 }
 
-// ---------------------------------------------------------------------------
-// Linear light field
-
-interface FieldPiece {
-  d: string;
-  clip: string[];
-}
-
-interface FieldGeometry {
-  pieces: FieldPiece[];
-  box: { x: number; y: number; w: number; h: number };
-}
-
-/** Bounded per-space cache: shape × radius × barrier revision (ТЗ §13.2). */
-export class LedFieldCache {
-  private entries = new Map<string, FieldGeometry | null>();
-  private space = '';
-  constructor(private readonly limit = 50) {}
-  get size(): number { return this.entries.size; }
-  /** Recompute counter for the performance witness: geometry, not paint. */
-  recomputes = 0;
-  forSpace(spaceId: string): void {
-    if (spaceId !== this.space) { this.entries.clear(); this.space = spaceId; }
-  }
-  read(key: string, build: () => FieldGeometry | null): FieldGeometry | null {
-    if (this.entries.has(key)) {
-      const value = this.entries.get(key) ?? null;
-      this.entries.delete(key);
-      this.entries.set(key, value);
-      return value;
-    }
-    this.recomputes += 1;
-    const value = build();
-    this.entries.set(key, value);
-    while (this.entries.size > this.limit) {
-      const oldest = this.entries.keys().next().value;
-      if (oldest === undefined) break;
-      this.entries.delete(oldest);
-    }
-    return value;
-  }
-  clear(): void { this.entries.clear(); this.space = ''; }
-}
-
-const pointsKey = (points: readonly number[][]): string =>
-  points.map((p) => `${p[0].toFixed(5)},${p[1].toFixed(5)}`).join(';');
-
-/**
- * Pieces of a strip for the field: stored segments cut to at most the radius,
- * each with the union of what its own emitters see (ТЗ §6). A piece whose
- * emitters are all inside a body emits nothing; a failed clip makes that piece
- * dark (fail-dark), never an unclipped field.
- */
-export function buildFieldGeometry(input: {
-  points: readonly number[][];
-  radius: number;
-  scene: LightBarrierScene;
-  polygons: readonly LightRoomPolygon[];
-  faces: FaceContext | null;
-  spaceId: string;
-}): FieldGeometry | null {
-  const path = compactPoints(pts(input.points));
-  if (path.length < 2 || !(input.radius > 0)) return null;
-  const r = input.radius;
-  const pieces: FieldPiece[] = [];
-  let minX = Infinity, minY = Infinity, maxX = -Infinity, maxY = -Infinity;
-  for (let i = 1; i < path.length; i++) {
-    const a = path[i - 1], b = path[i];
-    const len = Math.hypot(b[0] - a[0], b[1] - a[1]);
-    const count = Math.max(1, Math.ceil(len / r));
-    for (let k = 0; k < count; k++) {
-      const p0: Pt = [a[0] + ((b[0] - a[0]) * k) / count, a[1] + ((b[1] - a[1]) * k) / count];
-      const p1: Pt = [a[0] + ((b[0] - a[0]) * (k + 1)) / count, a[1] + ((b[1] - a[1]) * (k + 1)) / count];
-      const samples = emitterSamples([p0, p1], input.faces, r / 4);
-      if (!samples.length) continue;
-      const clip: string[] = [];
-      let failed = false;
-      for (const source of samples) {
-        try {
-          const lit = buildGlowClipGeometry({
-            spaceId: input.spaceId,
-            source: { x: source[0], y: source[1] },
-            radius: r,
-            scene: input.scene,
-            polygons: input.polygons,
-            onBoundsFailure: () => { failed = true; },
-          }).lit;
-          clip.push(...lit);
-        } catch {
-          failed = true;
-        }
-      }
-      if (failed || !clip.length) continue;
-      pieces.push({ d: `M${p0[0]} ${p0[1]} L${p1[0]} ${p1[1]}`, clip });
-      minX = Math.min(minX, p0[0], p1[0]); minY = Math.min(minY, p0[1], p1[1]);
-      maxX = Math.max(maxX, p0[0], p1[0]); maxY = Math.max(maxY, p0[1], p1[1]);
-    }
-  }
-  if (!pieces.length) return null;
-  return { pieces, box: { x: minX - r, y: minY - r, w: maxX - minX + 2 * r, h: maxY - minY + 2 * r } };
-}
-
-/** The shared falloff at a relative distance 0…1 (GLOW_FALLOFF, linear between stops). */
-export function falloffAt(fraction: number): number {
-  const at = Math.max(0, Math.min(1, fraction)) * 100;
-  for (let i = 1; i < GLOW_FALLOFF.length; i++) {
-    const [o0, v0] = GLOW_FALLOFF[i - 1];
-    const [o1, v1] = GLOW_FALLOFF[i];
-    if (at <= o1) return v0 + ((v1 - v0) * (at - o0)) / Math.max(1e-9, o1 - o0);
-  }
-  return 0;
-}
-
-const grey = (value: number): string => {
-  const level = Math.round(Math.max(0, Math.min(1, value)) * 255);
-  return `rgb(${level},${level},${level})`;
-};
-
-/** Stable DOM ids per strip: a re-render must not rebuild masks and clips. */
-const fieldIds = new Map<string, number>();
-const fieldId = (spaceId: string, stripId: string): number => {
-  const key = `${spaceId}|${stripId}`;
-  let id = fieldIds.get(key);
-  if (id == null) {
-    id = fieldIds.size + 1;
-    fieldIds.set(key, id);
-  }
-  return id;
-};
-
-export interface LedFieldInput {
-  views: readonly LedStripView[];
-  scene: LightBarrierScene | null;
-  polygons: readonly LightRoomPolygon[];
-  faces: FaceContext | null;
-  spaceId: string;
-  /** The card that owns the bounded cache (one per card, gone with it). */
-  owner: object;
-}
-
-const fieldCaches = new WeakMap<object, LedFieldCache>();
-export function ledFieldCache(owner: object): LedFieldCache {
-  let cache = fieldCaches.get(owner);
-  if (!cache) {
-    cache = new LedFieldCache();
-    fieldCaches.set(owner, cache);
-  }
-  return cache;
-}
-
-/**
- * The linear fields of the strips that are on in a Glow room. Fade uses the
- * shared spot transition (`.glow-spot`, GLOW_FADE_MS) — no animation system of
- * its own; an off strip keeps its node at opacity 0, so a fade-out completes
- * and leaves no residual light.
- */
-export function renderLedField(input: LedFieldInput): TemplateResult {
-  if (!input.scene) return svg`` as unknown as TemplateResult;
-  const cache = ledFieldCache(input.owner);
-  cache.forSpace(input.spaceId);
-  const scene = input.scene;
-  const fields = input.views.flatMap((view) => {
-    if (!view.glow || view.state === 'unavailable') return [];
-    const key = `${view.strip.id}|${pointsKey(view.strip.points)}|${view.radius.toFixed(5)}|${scene.fingerprint}`;
-    const geometry = cache.read(key, () => buildFieldGeometry({
-      points: view.strip.points,
-      radius: view.radius,
-      scene,
-      polygons: input.polygons,
-      faces: input.faces,
-      spaceId: input.spaceId,
-    }));
-    return geometry ? [{ view, geometry }] : [];
-  });
-  if (!fields.length) return svg`` as unknown as TemplateResult;
-  const bands = Array.from({ length: LED_FIELD_BANDS }, (_, k) => {
-    const outer = 1 - k / LED_FIELD_BANDS;
-    const inner = 1 - (k + 1) / LED_FIELD_BANDS;
-    return { half: outer, value: falloffAt((outer + inner) / 2) };
-  });
-  return svg`<g class="led-fields" pointer-events="none" aria-hidden="true">
-    ${repeat(fields, ({ view }) => view.strip.id, ({ view, geometry }) => {
-      const id = `${fieldId(input.spaceId, view.strip.id)}`;
-      const r = view.radius;
-      const on = view.state === 'on' && !!view.appearance;
-      const box = geometry.box;
-      const closed = isClosedStrip(pts(view.strip.points));
-      return svg`<g class="glow-spot led-field ${on ? '' : 'is-leaving'}" data-led-field="${view.strip.id}"
-          data-pieces="${geometry.pieces.length}" data-closed="${closed ? 'true' : 'false'}">
-        <defs>
-          ${geometry.pieces.map((piece, k) => svg`<clipPath id="hp-led-clip-${id}-${k}">
-            ${piece.clip.map((d) => svg`<path d="${d}" clip-rule="evenodd"></path>`)}
-          </clipPath>`)}
-          <mask id="hp-led-mask-${id}" maskUnits="userSpaceOnUse"
-            x="${box.x}" y="${box.y}" width="${box.w}" height="${box.h}"
-            color-interpolation="sRGB" style="mask-type:luminance">
-            <rect x="${box.x}" y="${box.y}" width="${box.w}" height="${box.h}" fill="black"></rect>
-            <g style="isolation:isolate">
-              ${geometry.pieces.map((piece, k) => svg`<g clip-path="url(#hp-led-clip-${id}-${k})"
-                  style="mix-blend-mode:lighten">
-                ${bands.map((band) => svg`<path d="${piece.d}" fill="none" stroke="${grey(band.value)}"
-                  stroke-width="${2 * band.half * r}" stroke-linecap="round" stroke-linejoin="round"></path>`)}
-              </g>`)}
-            </g>
-          </mask>
-        </defs>
-        <rect class="glow-pool led-pool" x="${box.x}" y="${box.y}" width="${box.w}" height="${box.h}"
-          fill="${view.appearance?.c ?? 'transparent'}" fill-opacity="${(view.appearance?.alpha ?? 0).toFixed(4)}"
-          mask="url(#hp-led-mask-${id})"></rect>
-      </g>`;
-    })}
-  </g>` as unknown as TemplateResult;
-}
-
 // ---------------------------------------------------------------------------
 // One frame for the card: the views of the shown space, its faces and scene.
 
@@ -583,6 +395,7 @@ export interface LedCardHost {
   _hideDeviceFocusTip: (id: string) => void;
   _renderProjection: string;
   _isoLightFloors: ReadonlySet<string> | null;
+  requestUpdate(): void;
 }
 
 const frames = new WeakMap<object, { key: unknown[]; frame: LedFrame }>();
@@ -665,7 +478,9 @@ export function renderLedLayerFor(
 
 export function renderLedFieldFor(host: LedCardHost, space: SpaceModel, spaceGlow: boolean): TemplateResult {
   const frame = ledFrameFor(host, space, spaceGlow);
-  return renderLedField({
+  const module = frame.scene && fieldWanted(frame.views) ? ledField(space.id, () => host.requestUpdate()) : null;
+  if (!module) return svg`` as unknown as TemplateResult;
+  return module.renderLedField({
     views: frame.views,
     scene: frame.scene,
     polygons: frame.polygons,
@@ -702,6 +517,8 @@ export interface StaticLedInput {
   bodies: { masonryGeometry: unknown; opaqueBodies: number[][][] };
   perUnit: number;
   owner: object;
+  /** Re-render when the field chunk lands. */
+  ready: () => void;
 }
 
 export function renderStaticLed(input: StaticLedInput): TemplateResult {
@@ -731,7 +548,9 @@ export function renderStaticLed(input: StaticLedInput): TemplateResult {
     occluders: [], floor: [], fingerprint: '',
     masonryGeometry: input.bodies.masonryGeometry, opaqueBodies: input.bodies.opaqueBodies,
   }, (LED_EPSILON_CM / input.cellCm) * input.gridPitch);
-  return svg`${input.scene && input.live ? renderLedField({
-    views, scene: input.scene, polygons, faces, spaceId: input.space.id, owner: input.owner,
+  const module = input.scene && input.live && fieldWanted(views)
+    ? ledField(input.space.id, input.ready) : null;
+  return svg`${module ? module.renderLedField({
+    views, scene: input.scene as LightBarrierScene, polygons, faces, spaceId: input.space.id, owner: input.owner,
   }) : nothing}${renderLedStripes({ views, d: frame.d, faces, perUnit: input.perUnit, handlers: null })}` as unknown as TemplateResult;
 }
diff --git a/src/space-render.ts b/src/space-render.ts
index 47ce9773..866e7404 100644
--- a/src/space-render.ts
+++ b/src/space-render.ts
@@ -999,6 +999,7 @@ export function renderSpaceStatic(o: StaticRenderOpts): TemplateResult | null {
           gridPitch: GRID_PITCH, iconPct, glowFor: (room) => !!o.lightPools && roomGlowOf(disp.glow, room),
           inRoom: (point, room) => pointInPolygon(point, roomPoly(room) || []), live: o.liveStates !== false,
           scene: lightScene, perUnit: pxPerUnit, owner: o.glowRuntime?.state || space,
+          ready: () => o.moonHost?.requestUpdate(),
           bodies: { masonryGeometry: canonicalWallGeometry?.components.flatMap((c) => c.geom) || [], opaqueBodies: extras },
         }) ?? nothing : nothing}
         ${wallUnion
diff --git a/test/bundle-assets.test.mjs b/test/bundle-assets.test.mjs
index 2abc8b38..6306f732 100644
--- a/test/bundle-assets.test.mjs
+++ b/test/bundle-assets.test.mjs
@@ -539,7 +539,8 @@ test('retry URL points at the content-hashed runtime chunk after naming', () =>
         + 'new URL("__HOUSEPLAN_FURNITURE_ART_RETRY_ASSET__", import.meta.url);'
         + 'new URL("__HOUSEPLAN_PDF_RETRY_ASSET__", import.meta.url);'
         + 'new URL("__HOUSEPLAN_MOON_RETRY_ASSET__", import.meta.url);'
-        + 'new URL("__HOUSEPLAN_LED_RETRY_ASSET__", import.meta.url)', modules: {},
+        + 'new URL("__HOUSEPLAN_LED_RETRY_ASSET__", import.meta.url);'
+        + 'new URL("__HOUSEPLAN_LED_FIELD_RETRY_ASSET__", import.meta.url)', modules: {},
     },
     // #627: the lazy namespace chunk that owns the nine second-attempt tokens.
     'houseplan-assets/backdrop-pick-HASH.js': {
@@ -584,6 +585,10 @@ test('retry URL points at the content-hashed runtime chunk after naming', () =>
       type: 'chunk', fileName: 'houseplan-assets/led-strip-runtime-HASH.js', code: '',
       modules: { '/repo/src/led-strip-runtime.ts': {} },
     },
+    'houseplan-assets/led-strip-field-HASH.js': {
+      type: 'chunk', fileName: 'houseplan-assets/led-strip-field-HASH.js', code: '',
+      modules: { '/repo/src/led-strip-field.ts': {} },
+    },
   };
   plugin.generateBundle({}, bundle);
   assert.equal(
@@ -596,7 +601,8 @@ test('retry URL points at the content-hashed runtime chunk after naming', () =>
       + 'new URL("./furniture-plan-art.generated-HASH.js", import.meta.url);'
       + 'new URL("./pdf-export-HASH.js", import.meta.url);'
       + 'new URL("./moon-runtime-HASH.js", import.meta.url);'
-      + 'new URL("./led-strip-runtime-HASH.js", import.meta.url)',
+      + 'new URL("./led-strip-runtime-HASH.js", import.meta.url);'
+      + 'new URL("./led-strip-field-HASH.js", import.meta.url)',
   );
   assert.equal(
     bundle['houseplan-assets/backdrop-pick-HASH.js'].code,
@@ -609,7 +615,7 @@ test('#627 namespace retry tokens stay strict: exactly one each, every chunk emi
     const bundle = {
       'houseplan-assets/houseplan-card.js': {
         type: 'chunk', fileName: 'houseplan-assets/houseplan-card.js', modules: {},
-        code: ['EDITOR', 'ONBOARDING', 'ISO', 'DE', 'FR', 'FURNITURE_ART', 'PDF', 'MOON', 'LED']
+        code: ['EDITOR', 'ONBOARDING', 'ISO', 'DE', 'FR', 'FURNITURE_ART', 'PDF', 'MOON', 'LED', 'LED_FIELD']
           .map((name) => `"__HOUSEPLAN_${name}_RETRY_ASSET__"`).join(';'),
       },
       ...Object.fromEntries([
@@ -618,7 +624,7 @@ test('#627 namespace retry tokens stay strict: exactly one each, every chunk emi
         ['iso-scene-render', '/src/iso-scene-render.ts'], ['de', '/src/i18n/de.ts'],
         ['fr', '/src/i18n/fr.ts'], ['furniture-plan-art.generated', '/src/furniture-plan-art.generated.ts'],
         ['pdf-export', '/src/pdf/pdf-export.ts'], ['moon-runtime', '/src/moon-runtime.ts'],
-        ['led-strip-runtime', '/src/led-strip-runtime.ts'],
+        ['led-strip-runtime', '/src/led-strip-runtime.ts'], ['led-strip-field', '/src/led-strip-field.ts'],
       ].map(([name, module]) => [`houseplan-assets/${name}-HASH.js`, {
         type: 'chunk', fileName: `houseplan-assets/${name}-HASH.js`, code: '', modules: { [`/repo${module}`]: {} },
       }])),
diff --git a/test/led-strip-runtime.test.mjs b/test/led-strip-runtime.test.mjs
index c438130c..64432f29 100644
--- a/test/led-strip-runtime.test.mjs
+++ b/test/led-strip-runtime.test.mjs
@@ -3,9 +3,8 @@
 import { test } from 'node:test';
 import assert from 'node:assert/strict';
 import { ledAnchor, ledStripsByMarker } from '../test-build/led-strip-gate.js';
-import {
-  LedFieldCache, buildFieldGeometry, falloffAt, faceContext, ledStripView,
-} from '../test-build/led-strip-runtime.js';
+import { faceContext, ledStripView } from '../test-build/led-strip-runtime.js';
+import { LedFieldCache, buildFieldGeometry, falloffAt } from '../test-build/led-strip-field.js';
 import { GLOW_FALLOFF } from '../test-build/glow-scene.js';
 import { stripAnchor } from '../test-build/led-strip-geometry.js';
 
diff --git a/tsconfig.test.json b/tsconfig.test.json
index 0fd18cb8..029a1bc0 100644
--- a/tsconfig.test.json
+++ b/tsconfig.test.json
@@ -17,7 +17,7 @@
     "src/radar-model.ts", "src/radar-editor.ts", "src/radar-geometry.ts", "src/radar-setup.ts", "src/radar-render.ts",
     "src/integration-provider.ts", "src/vacuum.ts", "src/vacuum-routes.ts", "src/vacuum-route-edit.ts",
     "src/sun.ts", "src/moon.ts", "src/moon-gate.ts", "src/moon-runtime.ts", "src/moon-art.generated.ts",
-    "src/light-visibility.ts", "src/led-strip-geometry.ts", "src/led-strip-gate.ts", "src/led-strip-runtime.ts", "src/glow-scene.ts", "src/space-render.ts",
+    "src/light-visibility.ts", "src/led-strip-geometry.ts", "src/led-strip-gate.ts", "src/led-strip-runtime.ts", "src/led-strip-field.ts", "src/glow-scene.ts", "src/space-render.ts",
     "src/resize.ts", "src/resize-labels.ts", "src/resize-controller.ts", "src/wall-record-preservation.ts",
     "src/rules.ts",
     "src/devices.ts", "src/device-inbox.ts",